Compass mechanism



Sept. 10, 1935. c. M. LEATHERMAN 2,014,024

' COMPASS MECHANISM Filed May 14, 1951 ezz ln/ventola CLARENCE MLE/ATHERMAN Patented Sept. 10, 1935 UNITED STATES ATENT OFFIQE 5 Claims.

This invention relates to a compass and especially such mechanism adapted for aerial navigation.

It is a special object of my invention to provide a compass of the type having a dial enclosed in a liquid container, with a setable indicator which may be moved relative to the dial to indicate any course desired and thereafter move relative to the dial to enable the navigator to guide his ship, if the compass is to be used thereon, on any given course without having to constantly read the indicia on the compass dial, but rather align a marker or sight on the setable indicator with the compass pointer, thereby simplifying the navigators work.

However it is to be understood that while my compass is especially advantageous for such use, it nevertheless is readily adapted for use in other forms of navigation, such as in submarines, steamships and the like. The essential and novel features of my invention will be brought out in the appended claims.

In the drawing Figure 1 is a vertical section, on an enlarged scale of the compass mechanism;

Figures 2 and 3 are fragmental verticalsections of the compass mechanism and are indicated by the lines 2-2 and 3-3 respectively on Figure 1;

Figures 4 and 5 are horizontal sections of the compass mechanism and are indicated by the lines 4--4 and 5-5 respectively on Figure l.

In the drawing my improved compass is designated by the numeral 20 and comprises a casing 2| provided with transparent top and bottom plates 22 and 23 respectively. Within the casing is a compass dial 24 and a setable indicator 25, lboth of which are translucent.

The compass frame or case 2| is cylindrical in form, has top and bottom closure plates 22 and 23 of clear glass, and provides a liquid receptacle.

Rigidly secured to the inner wall of the compass case or frame 2| is a bracket |30 which eX- tends adjacent the bottom wall 23 of the compass case and some distance beyond the axis thereof. J ournalled in this bracket |30 is a shaft 3| extending vertically upward from the bracket |30 along the axis of the case 2|. A second bearing member |32 is secured to the bracket |30 at |33 and assists in maintaining the alignment of the shaft 3|. interposed between the bearing members |30 and |32, and rigidly secured to the shaft |3|, is a worm gear |35 adapted to mesh with a worm |36, (Fig. 5) the rotation of which causes the shaft I3! to rotate in its bearings for a purpose to be hereinafter described. The worm gear |35 also acts as a set collar to prevent longitudinal movement of the shaft |3| in its bearings.

Adjacent the upper end of the shaft |3| and rigidly secured thereto is a pivot seat bearing |31 adapted to support the compass dial 24 and its 5 associated parts. The compass dial 24 is rigidly secured to the outwardly flanged bottom edge of a cylindrical frame |38, (Figs. 1, 2 and 4). The upper end of this frame |38 is provided with suitable cross members |39, to which is rigidly 10 secured a pivot pin |45, having a point 4| adapted to coact with a conical seat |42 formed in the upper end of the shaft |3|.

To prevent distant separation between the pivot pin |40, and its seat |42, and likewise prel5 vent excessive tilting of the dial relative to the compass case, I secure a bell or hemi-spherical cup |44 to the pivot pin |40. Secured to a bushing |45, rigidly carried by the shaft |3l, is a cylinder or shell case |46 having upwardly and inwardly 20 curved arms |47 which are spaced apart from and follow the contour of the bell |44 as shown in Figs. 1 and 2. The upward movement of the bell |44, the pivot pin |40, the frame |33 and dial 24, relative to the shaft |3|, is therefore limited 25 to the distance between the bell |44 and the shell case |46. The upper end of the shell case |46 is provided with an opening |48 of such a diameter as will permit free rotation and oscillation of the pivot pin |40 and dial 24, but, at the 30 same time prevent excessive tilting of the dial 24 relative to the compass case.

Resting on the top face of the dial 24 is an indicator arm 25, which like the dial is made of a clear transparent material and has painted or 35 otherwise impressed thereon a translucent colored bracket |40 provided with pointers |50, and the indicator is provided with a cylindrical opening |5| by means of which the indicator 25 is journalled on the frame |38. The indicator 25 40 is also provided with an arm |52 extending diametrically from the indicator |49, beyond the outer edge of the dial 24 and serves a purpose to be hereinafter described. The dial 24, the indicator 25 with its arm |52, the bell |44 and the 45 frame |38 are all in perfect balance on the pivot seat |42 and are free to rotate thereon, due entirely to the influence of the earths magnetism. As is usual in Compasses of this type, the case 2| is lled with a light non-viscous liquid and entirely free from air.

The arrangement of the compass 20 is such that the pilot may readily change the relationship between the compass dial 24 and the indicator 25 thereby setting his course on the dial. This is 55 pointer and prevent its rotation when the dial mechanism is raised from its seat whereby the dial may be rotated through said gearing to change its position relative to the pointer.

4. A compass including a case, supporting means in said case, including a vertical shaft, a dial mechanism pivoted on the upper end of said shaft, a pointer carried by the dial and rotatable thereon, means to clutch the shaft to the dial mechanism, means to engage the pointer to retain the same iixed relatively to the casing, means to rotate said shaft, and means operable by said rotating means to substantially simultaneously render operative said clutch means and pointerengaging means whereby the pointer may be adjusted relatively to the dial mechanism by rotating the shaft.

5. A compass including a liquid receptacle, supporting means in said receptacle, including a vertical shaft, a dial mechanism pivoted on the upper end of said shaft, a pointer carried by the dial and rotatable thereon, means to clutch the shaft to the dial mechanism, means to engage the pointer to retain the same fixed relatively to the receptacle, means to rotate said shaft, and means operable by said rotating means to substantially simultaneously render operative said clutch means and pointer-engaging means whereby the pointer may be adjusted relatively to the dial mechanism' by rotating the shaft. 

